• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.7 no.4
• /
• pp.528-535
• /
• 1997

$LiTaO_3$ single crystals of congruently melting composition were grown by the halogen lamp type floating zone system. Calcination and sintering parameters for the growth were established. Optimum crystal growth conditions were investigated by a controlling of growth rates, rotation speeds and atmospheres. Based on the melting aspect and the shape of molten zone, stable conditions could not be found in air or Na atmosphere. However the growth stability in Ar atmosphere was more regular than that in air or $N_2$. The grown crystals were characterized using Laue back reflection, Curie temperature, refractive index and transmittance. Curie temperature fluctuation in the section of the grown crystal part of top, body and tail was $1^{\circ}C$.

• Applied Microscopy
• /
• v.33 no.3
• /
• pp.215-222
• /
• 2003

The ultrastructure of damaged hair shaft from blow-drying at typical temperature $40{\sim}170^{\circ}C$ for daily beautiful face have been investigated by using transmission electron microscope and scanning electron microscope. When we used to hair dryer for a long time in our everyday life, the following morphological alternations were found in hair. First, the partial of scales in outer cuticle were detached simultaneously with separation of intercellular membrane complex of cuticle cells. Then hair broke cuticle off and exposed to cortex. Secondly, the cortical cell in the cortex was fissured into its macrofibril. The melanin granules were scattered between macrofibrils. As a result, I confirmed that blow-drying removed the hair's bonded water and made hard on hair which lost elasticity. After all, hair showed irregular, rough surface and vanished its luster.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.1152-1155
• /
• 2007

Lately concerns about structure have been increased by advantages of floor impact noise, poilitical induction and changeability. Hence, Flat Plate Structure has been constructed increasingly. This study shows the comparison of the performance of sound insulation of Flat Plate Structure System and the existing Wall Structure. For this study, taking the same level organization of Daelim Architectural Environmental Research Center, I found the performance of sound insulation between the upper and lower floors about Wall Structure and Flat Plate Structure. Consequently, the performance of sound insulation between upper and lower floors of Flat Plate Structure was 3-5dB higher was approximately 3-5dB higher than one of Wall Structure. Especially, the performance of sound insulation on the upper floor was 1-3dB higher than on the lower floor. In addition, as the result of comparing radiation sound which radiates from the wall of lower floors with each structure system, Flat Plate Structure was about 4dB higher with Rw than Wall Structure. As we see totally, the performance of sound insulation of Flat Plate Structure is highter than one of the Wall Structure. It is 3-5dB higher and the main reason for this result depends on the existence of the wall which can radiate sound and nonexistence.

• Journal of Korean Society for Atmospheric Environment
• /
• v.16 no.4
• /
• pp.381-388
• /
• 2000

Ceramic foam prepared with cordierite as a starting material by foam method was tested to evaluate the feasibility as a filter for the dust collection in hot gas. Two different types of agents Benzethonium chloride (BZTC, C27H42NO2Cl) and Sodium Lauryl Sulfate(SLS, CH3(CH2)11OSO3Na) were used as foaming agents in foaming process. Porosityof ceramic foam was about 80% and mean pore size were 100${\mu}{\textrm}{m}$ for SLS agent and 200 ${\mu}{\textrm}{m}$ for BZTC. It was observed that ceramic foam was composed of continuous macro-pore structure with opening windows interconnecting macro-pores. The surface of ceramic foam support of was coated with cordierite particles ranged from 20${\mu}{\textrm}{m}$ to 50${\mu}{\textrm}{m}$ Meso-pore size in the coating layer on ceramic foam was below 10${\mu}{\textrm}{m}$. While air permeability of the support increased with increasing macro-pore size coated ceramic filters showed a constant permeability without regard to the macro-pore size of the support. The permeabuilities of support varied in the range of 600$\times$10-13m2 to 1000$\times$10-13m2. For the case of coated ceramic filter it was about 200$\times$10-13m2. As a result of particle trapping test by using fly ash the particle removal efficiency was over the 99.9%.

• Journal of Fashion Business
• /
• v.9 no.1
• /
• pp.113-119
• /
• 2005

In our previous study, the color development characteristics in the dyeing of silk fibers and PET fibers using Rhusjara ica and related properties were meticulously reviewed. At the same time, the fabric specimens were endowed with chitosan treatment prior to the dyeing procedure in order to investigate the effect of chitosan on the dyeing behavior. The analysis of the colors only, however, would not give us complete elucidation of the effect of fiber characteristics and the mordanting characteristics. In this study, the effect of chitosan and metal mordant treatment in dyeing of silk and PET fabrics using Rhusjara ica has been studied. The change of air-permeability, wash fastness, and light fastness were also investigated.

• Analytical Science and Technology
• /
• v.7 no.3
• /
• pp.349-359
• /
• 1994

A gas chromatographic method for analyzing the gas odorants concentration in natural gas was studied. Eight odorants involving TBM and THT were completely separated by using OV-10 column. The optimization of several interrelated key parameters affecting the response of FPD such as hydrogen flow rate, air flow rate and detector temperature were accomplished. A permeation device was used to obtain calibration curves of TBM and THT. This analytical method has applied to measure TBM and THT used as a natural gas odorant blend in natural gas pipeline. In order to elucidate the relationship between odor level and odorant level feasibility test of fragrance meter was demonstrated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2009.04a
• /
• pp.342-350
• /
• 2009

Fuel cells convert a fuel together with oxygen in a highly efficient electrochemical reaction to electricity and water. Since the electrochemical reaction in the fuel cell stack dose not generate any noise, Fuel cell systems are expected to operated much quieter than combustion engines. However, the tonal noise and the broad band noise caused by a centrifugal compressor and an electric motor cause which is required to feed the ambient air to the cathode of the fuel cell stack with high pressure. In this study, the multi-camber perforated muffler is used to reduce noise. We propose optimized muffler model using an axiomatic design method that optimizes the parameters of perforated muffler while keeping the volume of muffler minimized.

• Journal of the Korean Home Economics Association
• /
• v.20 no.3
• /
• pp.19-24
• /
• 1982

This study was carried out to investigate the relationship between the water resistance and the air permeability. The results are as follows; 1. In case of the water proofing fabrics, We cannot find that there is any relationship between the water resistance and the air permeability according to the kinds of finishing, while in case of the water repellent finished fabries, we can find that there is a correlationship between them, especially the hydrostatic pressure and the air permeability are found to have negative correlation. 2. In case of the water proofing fabrics, the relationship between the water resistance and the air permeability is not affected by the thickness of the fabrics. On the other hand, in case of the water repellent finished fabrics, the relationship between them is affected by the thickness of the fabrics. Especially, the relationship between the hydrostatic pressure and the air permeability as well as the relationship between the water repellency and the air permeability is effect much by the thickness of the fabrics, too. 3. In case of the water proofing fabrics, the relationship between the water resistance and the air permeability is not affected by fabric count. On the otherhand, in case of the water repellent finished fabrics, the relationship between them is affected by the fabric count. Especially, the relationship between hydrostatic pressure and the air permeability, and the relationship between the water proof and the air permeability are affected much by fabric count.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.22 no.7
• /
• pp.807-815
• /
• 1998

Functions of interlinings to the shell fabric are to improve the garment formability for a beautiful silhouette and elastic potential to the deformed fabric during wearing, and also are to enhance appearance and wearing properties of garment. The objective of this study is to analyse the thermal properties of nonwoven fusible interlining to the thin worsted fabric with various fabric structural parameters. For the purpose fo this study, eight specimens with various weft yarn twists and weft densities of thin worsted fabrics are prepared. Three nonwoven fusible interlinings with different structure which were made by Nylon/Polyester were used for adhering to the thin worsted fabrics. Thermal properties of these 24 adhesive fabrics fused with 3 nonwoven interlinings are measured by KES-F7 System for analysing the thermal suitability of nonwoven fusible interlinings to the thin worsted fabrics with various fabric structural parameters. And air permeability, which was measured by KES-F8-API, of 24 nonwoven adhesive interlining fabrics was also analysed and discussed with the various kinds of nonwoven interlinings and fabric structural parameters.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.36 no.2
• /
• pp.191-196
• /
• 2016

Applying diffraction of waves and muffler principle, the theory of macroscopic air ventilation with soundproofing was explained. Soundproofing frequency range can be selected by this method. The sound wave was attenuated at the resonator located between double-layered walls. A soundproof plate was designed and the experiment was processed. There are two air holes of diameter of 5cm and thickness of 8cm on the surfaces per each soundproofing cell. There was a transmission loss of about 25dB and it is more than at least 10dB compared with that of the Comnex technology of wave cancellation by air holes in Japan. Furthermore, there was no soundproof frequency selection in the Comnex technology.